Spotted knapweed, Centaurea biebersteinii DC. (C. maculosa Lam.), an exotic invasive aster native to Europe and Asia, is only officially documented to be found within natural and disturbed areas of 18 counties in eastern Tennessee, although it is known to occur in others. While no biological control agents of spotted knapweed have been released in Tennessee, several phytophagous insects such as Urophora quadrifasciata (Meigen) (Diptera:Tephritidae) and Megalonotus sabulicola (Thomson) (Heteroptera:Lygaeidae) have been either released or unintentionally introduced within states close to Tennessee to combat the spread of spotted knapweed. Populations of spotted knapweed in 20 counties were surveyed and sampled for the presence of biological control organisms during their various life stages using direct sampling, sweep netting, beat sheeting, seed head dissection and plant dissection. Results indicating the incidence and distribution of biological control agents that are now associated with spotted knapweed within eastern Tennessee will be presented.
Species 1: Diptera Tephritidae Urophora quadrifasciata
Species 2: Heteroptera Lygaeidae Megalonotus sabulicola
Species 3: Asterales Asteraceae Centaurea biebersteinii (spotted knapweed)
Keywords: biological control, weed management
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